Related Party Transactions (Detail Textuals) (Board Of Directors, USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Board Of Directors
Related Party Transaction [Line Items]
Legal fees and disbursements	$ 129,000	$ 71,000

Represents the amount of expense provided in the period for legal fees and disbursements.

No definition available.

Name:	svt_LegalFeesAndDisbursements
Namespace Prefix:	svt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration